Implement <sys/fsuid.h>.

(cherry picked from commit 79310994d2b3826a10598f7e7795acb5edb42a20)

Change-Id: I47688273691e5c95e5e9302eba254ccaaaad40ca
diff --git a/libc/arch-arm64/syscalls/setfsuid.S b/libc/arch-arm64/syscalls/setfsuid.S
new file mode 100644
index 0000000..852f97c
--- /dev/null
+++ b/libc/arch-arm64/syscalls/setfsuid.S
@@ -0,0 +1,14 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(setfsuid)
+    mov     x8, __NR_setfsuid
+    svc     #0
+
+    cmn     x0, #(MAX_ERRNO + 1)
+    cneg    x0, x0, hi
+    b.hi    __set_errno
+
+    ret
+END(setfsuid)